This invention relates to an image pickup system which is to be used in combination with a craft (such as a spacecraft, an aircraft, or the like) flying over an object zone (such as a ground surface of the earth or the like) which is to be imaged.
An image pickup system of the type described is used to remotely survey or sense an object zone, from a position on board a craft flying over the object zone along a flight path. It is often desirable to develop a stereo topographic image of the object zone by the use of such an image pickup system. In order to provide the stereo image, each object zone should be sensed along the flight path at two positions spaced apart from each other, so as to form two optical images of each object zone.
It is difficult to derive two optical images of the above-described type on a single craft at the same time in the usual manner. Therefore, it has been proposed to derive the stereo image with a displacement of the craft.
As will later be described with reference to FIGS. 1 and 2 of the accompanying drawing, a conventional image pickup system has at least two optical systems for deriving the stereo image. The conventional image pickup system is therefore heavy and bulky as compared with a conventional image pickup system which derives a nonstereo image. This makes it difficult to load the craft with the system. Moreover, at least two optical systems must be precisely adjusted with respect to each other. Such adjustment is very difficult and troublesome.
It is also often desirable to provide a topographic (or similar image at a high resolution so as to make up a precise topography or the like. This makes it necessary to receive and increased number of successive image signals on board the craft. It is often necessary to transmit these signals from the craft to terrestrial stations.